Side-bolt construction



E. E. LEAR vSIDE BOLT' CONSTRUCTION Filed NOV. 14 1925 v INVENTORl 'W E021/ fav July 2o 192e.

Cil

Patented July 20, 1926.

UNITED#s'm'rns 1,592,858 PATENT OFFICE.

EARL B. LEAR, OF .'PHLLIPSBURG, NEW JERSEY, ASSIGNOR TO INGERSOLL-RAND COMPANY, F JERSEY CITY, NEW JERSEY, A CORPORATION OF NEW JERSEY.

SIDE-BOLT CONSTRUCTION.

Application filed Novemberl/l, 1925. Serial No. 68,967.

This invention relates to percussive rock drills but more particularly to means for assembling the different elements in a rock drill in such a way that a great rigidity can i be secured and vibration and jar absorbed while at the same time no excess strain is placed on the coil springs used for this purpose. Heretofore, with the customary assembly by means of side bolts and coil l0 s rings the s rings have been sub'ected to,

P e a P s unduly great compression strains and frequent breakage of the said springs results when the drills are put in operation.

The object of my invention therefore l is to provide means whereby the coil springs and side bolts can be compressed to a certain point after which they are protected from any additional strain by means of a sleeve or buttress which fits over the side Z0 bolts. At the same time the springs are allowed to remain unhampered when absorbing the shock due to the downward blow of the hammer piston of the rock drill. My invention consists of the features of novelty and the combinations of elements substantially as described in this specication, set forth in the appended claims, and illustrated in the accompanying drawings in which,

Figure l is a side view of a rock drill '30 partly in vertical section and partly broken away showing the invention applied thereto, and

Figure 2 is a transverse sectional view on the line 2-2 of Figure l looking in the direction of the arrows.

Referring to the drawings, the back head A, the cylinder B and the front head C of a percussive rock drill are shown held in fixed relation to each other by means of the side bolts D,the coil springs E and lock nuts F which parts cooperate with the usual lugs G, H and J on said back head, cylinder, and front head respectively. The lugs G and H are bored so that the side bolt D will have a substantially close lit therein. The lugs J are bored to a larger diameter than the bores of the lugs Gr and H in order to allow the side bolts D and sieeves K to fit slidably within the bore. Each sleeve K is of a form substantially as shown in Figure l 4of the drawing, being a cylinder open at both ends with a bore enabling the side bolt D to fit slidably within it and an outside diameter such that it will fit slidably within the bore in a lug J but will abut against the front face of a lug H. A head or circular abutment L is on the other end of the sleeve such that the forward end of the coil spring E 'will abut against it. The coil spring E is f of the usual design, but the inside diameter is W such that it will fit over the sleeve K. An important element of the invention resides in the relative length of the sleeve K which must be determined by the amount of compression it is desired to give the coil spring G5 E. The assembly of the device on a percussive rock drill is also substantially as shown in the drawings. After the back head A, cylinder B and front head G have been fitted together the side bolts D are run through H3* the lugs Gr and H while the sleeves K with the coil springs E are run over the side bolts D from the other end and the sleeves themselves are run lthrough the lugs J. The customary lock nuts and washer F are then 'l screwed on the end of the side bolts D and are drawn up against the compression of th springs E until the ends of the sleeves abut against the front faces of the lugs H. l/Vhen this has occurred, the springs O can not 30 be compressed any further and remain thus positively protected so long as the assembly remains in good condition. On the other hand the function of the springs E as cushioning means in order to absorb the vibration and' jar of the rock drill when in operation, is nowise impaired. I am not to be understood as describing speciiically the exact and precise means of applying my invention to percussive rock drills but merelya preferential method of application and assembly, said application and assembly always to be modilied by the type of drill or by its intended use.

Iv claim:

1. An improvement in the side bolt assembly of a percussive rock drill comprising a sleeve adapted to t over a side bolt and -to be held between lock nuts on the end of the side bolt and lugs on the cylinder, a coil spring adapted to fit over the said sleeve, and to be carried wholly by the said sleeve, and means whereby the said spring can be compressed to a predetermined point after` which the compression strain is assumed wholly by the lugs formed on the cylinder and the cylinder back head.

2. An improvement in the side bolt assembly of a percussive rock drill comprising a sleeve adapted to lit over a side bolt and to said bore, a bore in said cylinder lug of smaller diameter suilieient only to rallow the said side holt to tit therein,v a coil spring; adapted to he carried Wholly by the said sleeve, an abutment on the said sleeve at its forward end for engagement with the said coil spring, the front end ot' the said liront head lug` i'ormingA a stop for engagement with the other end of said spring; and the forward end of the said cylinder lugforming` a stop for engagement with the rear- Ward end of said sleeve, the sleeve'being of suiieient length to limit compression of the coil spring whereby the sleeve will permit compression oi' said spring' against the front head lugl until a predetermined compression is reached whereupon the rearward end ofthe said sleeve Will abut against the said cylinder lug and transmit any additional strain to the said cylinder lug.

In testimony Whereol1 I have signed this specilieation.

EARL B. LEAR.

he held in place by look nuts on the front end of the side holt, a coil spring adapted to lit over the said sleeve and to he carried Wholly by the said sleeve, an abutment at the front end of said sleeve for the front endr of said spring, a hearing between the rear end of said sleeve and the cylinder' lug, and an abutment between the reai` end of said spring and the front head lug, whereby the; said coil spring is protected fromriundue eompressionalstress by means of the said sleeve. Y

3. An improvement in the side bolt assembly of a peroussive rock drill comprising lugs on the bask head, cylinder and front head of said pereussive rook drill, a side bolt in engagement with the said lugsfa sleeve adapted to tit over the said side holt and to he carried Wholly on said side bolt, lock nuts on the said side holt holding` the said sleeve in place, a bore in said front head lug of suioient diameter to allow the said sleeve to slidably extend through the 

